1. Field of the Invention
The present invention relates to cleaning devices used in image forming apparatuses such as a copying machine, a printer, and a facsimile machine, and also relates to image forming apparatuses provided with the same.
2. Description of the Related Art
Generally, an image forming apparatus includes an image bearing member, and a toner image formed on an image forming surface of the image bearing member is transferred to a sheet at a transfer nip portion. There have been known a cleaning device which performs a cleaning processing of removing toners remaining on the image forming surface after a transfer processing is performed (for example, refer to Japanese Patent Unexamined Publication No. 2006-184885), and a cleaning device which applies a lubricating agent to the image forming surface (for example, refer to Japanese Patent Unexamined Publication No. H07-271142).
In the former apparatus, a cleaning brush is provided so as to be capable of coming in contact with or being separated apart from the image forming surface. The brush comes in contact with the image forming surface, so that the image forming surface is cleaned. In the latter apparatus, a solid lubricating agent is provided near the brush. The lubricating agent comes in contact with the brush, so that the lubricating agent is applied to the image forming surface through the brush. Accordingly, the surface friction factor of the image forming surface can be suppressed to be low.
Meanwhile, the brush with which the above-described lubricating agent comes in contact has an axis line extending along a direction in which the transfer nip portion is formed, and an axis line of the solid lubricating agent also extends so as to be substantially parallel to the axis line of the brush. It is preferable that the solid lubricating agent comes in contact with the brush evenly along its widthwise direction. This is because, if the lubricating agent has a contact parts and noncontact part with respect to the brush, it is necessary to perform maintenance for the lubricating agent frequently.
Further, a sheet to which the toner image is transferred includes a smoother for smoothing the surface of the sheet. Further, it should be noticed that a developer supplied to the image forming surface includes not only toners but also an external additive for toner used for polishing the surface of the image forming surface. This is because while the smoother and the external additive for toner achieve a desired function, they may contaminate the image forming surface and opposite end portions of a sheet.
As described above, a cleaning device needs some measures for making the lubricating agent be maintenance-free and enhancing image quality, but the conventional technologies described above do not take this point in consideration.